[docs] Updated development documentation
[vbox] Created folder for iso in virtualbox
Merge pull request #1322 from aglarendil/master

update submodules
Merge pull request #1321 from Mirantis/docs

Updated development documentation
More packages for fuel
Merge pull request #1327 from Mirantis/up-req

More packages for fuel
Update ostf link
Merge pull request #1328 from Mirantis/up-ostf

Update ostf link
Changed virtualbox scripts to use Intel 1Gbps NICs
fixed virtualbox scripts to set video memory to 16MB, so it does not complain about non-optimal VM settings in the UI
enabled host i/o cache. it seems to work better with ext4 partitions inside guests
reduced disk sizes in VirtualBox scripts down to 16, 32, and 64GB. previously the largest dist was 2TB, and it was taking 5+ minutes to format it to ext4. this is unacceptable for the end users of VirtualBox scripts
Fake RHEL validator
Unit tests for fake RHEL validation
Fix unit tests
Add RH credentials test
Fake Red Hat validation
Fix unit tests
Update mocks for unit tests
Fix merge issues and tests